Engine suspension



Dec. 6, 1949 J. M. TYLER ETAL ENGINE SUSPENS ION 3 Sheets-Sheet l Filed Jan. l, 1945 Hgeza "lll/f/ Dec. 6, 1949 Filed Jan. l, l

J. M. TYLER ET AL ENGINE SUSPENSION 3 `Sheets-Sheet 2 INVENTOR Joau M. 7,227/ Z er ygen Dec' 6,

J- M. TYLER ET AL ENGINE SUSPENSION 3 Sheets-Sheet 3 Filed Jan. 1I 1945 Patented Dec. 6, 1949 ENGINE SUSPENSION John M. Tyler and Andrew V. D. Willgoos, West Hartford, Conn., assignors to United Aircraft Corporation, East Hartford, Conn., a. corporation of Delaware Application January 1, 1945, Serial No. 570,840

11 Claims.

This invention relates to improvements in the suspension of Iaircraft engines.

An object of the invention is to provide improved suspension means for aircraft engines by which an engine is supported in two planes transverse to the longitudinal axis of the engine and at widely spaced locations along said axis.

A further object of the invention is to provide a two-plane engine suspension system of the above type for use on engines having an eXtension shaft drive to a propeller separately mounted on the aircraft structure.

A still further object of the invention is to provide a two-plane engine suspension system in which an engine is supported, in effect, on two bearings at spaced locations along its axis of rotation, one of which is located adjacent the drive end of the engine and has no radial flexibility and no stiness resisting torsionally applied loads and the other of which is located toward the other end of the engine and includes exible attachments to the aircraft frame structure which are flexible in the direction of radially and torsionally applied loads.

Another and related object of the invention is to provide a two-plane engine suspension system in which the mount in the plane adjacent the drive end of the engine resiliently resists fore and aft movements of the engine and provides controlled irictional damping of torsional vibrations of the engine.

A further object of the invention is generally to improve the construction and performance of engine mounts.

Other objects and advantages of the invention will be apparent from the following description and from the accompanying drawings which illustrate one embodiment of the invention.

In the drawings,

Fig. 1 is a side View of one form of two-plane engine suspension constructed in accordance with the invention;

Fig. 2 is a view from the right hand end of Fig. 1 showing the arrangement of the engine supporting frames of one of the mounts;

Fig. 3 is a View of the other mount from the left hand end of Fig. 1;

Fig. 4 is an elevation, partly in section, of the mount of Fig. 3 on a much enlarged scale;

Fig. 5 is an enlarged detail of one of the frames shown in Fig. 2;

' Fig. 6 is a section on line 6 6 of Fig. 5;

Fig. 7 is a section on line 1-1 of Fig. 5;

Fig. 8 is a section through the flexible attachment and certain of the ring carried parts which 2 cooperate therewith taken in the plane of the ring;

Fig. 9 is a detail of a portion of the ring as viewed from the center thereof; and

Fig. l() is a section on line |0-I0 of Fig. 5.

As shown herein; a radial aircooled engine l0 (which may bel the engine shown and described in detail in the Hobbs-Willgoos Patent No. 2,426,- 879, assigned to applicants assignee) having a longitudinal crankshaft I2 and radially disposed cylinders ill is supported in a submerged position in -a wing I5 of an aircraft by engine mounts A and B located in planes transverse to the longitudinal axis of the engine and at spaced locations along said axis. While the engine illustrated is4 of the radial type and is shown submerged in a wing of the aircraft, it will be evident that the invention is equally applicable to the suspension of other types of engines and to the support of these engines on other structural members of the aircraft.

Referring first to mount B shown in Figs. 1 and 2 and in detail in Figs. 5 to 10, inclusive, it will be noted that a mounting ring I6 of annular cross-section is supported on the aircraft structure at diametrically opposite points on its periphery by brackets I8 (Fig. 2). Each of these brackets comprises two plates having complemental arcuate grooves formed in confronting faces thereof to receive peripheral portions of the ring l@ to the opposite sides of which they are rigidly clamped by four through bolts 20. of the plates of each bracket is formed with a ilange 22 which is detachably secured by two bolts 2li to wing ribs, one of which is shown at 28. The ring I6 is further supported at the top thereof by a bracket 25 provided with a vertical ring receiving slot which permits movement of the ring relative to the bracket in a vertical direction. It

will be evident Afrom Figs. 1 and 2 that the ringA it is supported in the vicinity of the blower casing 30 with its center coincident with the axis of crankshaft l2 of the engine, and further that the plane of the ring I6 is disposed perpendicular to the engine crankshaft axis.

The engine is connected to the ring l5 by a plurality of A-frames which are spaced peripherally about the engine and ring and comprise rigid inwardly divergent legs, or struts, 32 which lie in the plane of the ring. Each of the struts 32 has an offset, radially directed inner end portion which is bifurcated and which is connected by a bolt 34 to the tongue of a bracket 35 secured by cap screws 38 to pairs of peripherally spaced pads 40 on the engine blower casing (see 3 Figs. 2 and 6). At its outer end each pair of the struts 32 is rigidly connected to one part 42 of a two-part head the other part 44 of which comprises a cap secured to the part 42 by a pair of through bolts 48. The parts 42 and 44 have complemental recesses 48 and 50 therein forming a chamber which encloses a portion of the -crosssectional periphery of the ring,` the chamber providing suilcient space in the plane of the ring to receive resilient mount elements 52 and 54 on opposite sides of the peripheral portion of the ring enclosed by the head. It will be understoodthat,

these elements are compressedbetween the head parts 42 and 44 and the ring [6 asthebolts 48 are tightened so that the rubber. of elements 52 and 54 is under some initial co'imres'sion.vv Each resilient element is provided with an arcuate metal shell 56 having flanges 58 whichy overlie the recesses 48 and 5U against vmovement in a direction'at right angles thereto. The elements 52 and 54 are positioned against movement about the cross-sectional periphery of the ring by arcuate shells 6B which abut the edges of spaced plates 62 welded to diametricallyopposite faces` of the cross-sectional periphery of the ring.l The elements 52 and 54 may also be provided with metal inserts 66 in a well known manner to vary the stiiness thereof, the rubber of these elements being permanently bonded to the shells 56 and 60 and to the inserts 6B in the usual manner.

i Suitable stops 68 are provided on the inside of the ring I6 at opposite sides of the heads to prevent excessive torque windup. It will be noted that in the no-torque positionof the parts, as shown in Fig. 8, the head is located adjacent the lefthand stop 68 so that when the engineis developing normal torque the head'will be located substantially midway between the stops. Arcuate strips 1l] are welded to theinside and outside of the ring in position to center the inner shells Sncf-the resilient elements, these stripshaving adjacent inclined surfaces 12 'whichv act to guide any shell 6i! into its normal VVpositionon the ring it becomes separated therefromV due to vextreme compression of the opposite element resulting from high maneuver loadhconditions.

The mount A, shown mostclearly in Figs. 3 and 4 is located at the propeller endlof theengine and includes a bracket 14 secured to the enginecrankcase by studs 16. The bracketV 14 hasaforwardly` extending annular flange 18 the outer surface of which is provided with radially outstanding flanges 80 and 82 providing a atannular groove 84 for receiving a band 86V of ,yieldable ,but rela-` tively stiif friction materialV such as the ymaterial. conventionally used in brake linings.. The band may conveniently beformed of two semi-circular sections which are held in place Yin the groove by a hanger 88 which has a like lconfronting groove 90 formed therein by flanges 9|. and 92Asimilar to the flanges 80 and 82. The hanger also is made in two parts, the upper supportingapart being connected by means of upwardly diverging struts 94 and 96 and bolts 91 with. the structural frame of the aircraft, and the lower part 98..being re. movably detached to part 9,3vby capscrews [80. It will be noted that the thickne'ssfof-band 85 is such that the confronting flanges .91, 80 l'and 92., 82 are spaced apart by the bandwhichforrns an annular key to interlockthe` hanger and bracket members 88 and 14 in a fore and aft direction While also supporting the engine at this point with a minimum of radial exibility. This construction holds the engine against lateral movement at mount A which is desirable because the crankshaft l2 is connected at this location with a spline drive |02 with which it is essential that the engine be maintained in accurate alignment.

It will thus be evident that, since the mount A constitutes aY bearing for supporting the engine at the drive end thereof, engine torque is carried entirely by the flexible mount B at the end of the. engine remotefrom the drive end through shear of the rubber segments of the elements y52 and 54. Radial g loads, i. e. loads imdrive end, although some resiliencyis Dl'QVided:

at mount B. It will also be evident that, with the legs 32 of the A-frames. disposed in a plane, perpendicular to the icrankshaft axis and with.. the pivots 34 connecting these legs to the brackets,

36 also lying in this plane, bending loads at the attachment of the brackets. 38 to the blower housing 30 due to foreand aft movements of the engine are practically eliminated.

4Fore and aft "g loads from.v the engine,

taken through the damper band 8G as shear loading. This band also acts to suppress torsional vibration of the 'engine by imposing fricf tional resistance to rotation of the engine vat.` tached bracket 14 with respect to the hanger. 88. If desired, a few thousandths of an inch clearance may` be provided between the damper band 86 and the adjacent surfaces'84 and 9J l,so-l

that when the engine is at `rest contactbetween the band and surfaces 84 and 90-will occur only` at the bottom. Then when torque is appliedv to the engine and it rotates,lin effect, in its two' bearings provided by mounts A and B, the any` nular surface 8.4,willA roll on theband 85 so that the point of contactbetween the band and surf' faces 84 and -90' will move up along one .side of the circumference ofthese surfaces. When the verticalicomponent of load at the point of con-` tact becomes large enough, sliding will jtake. place and the point of contact will move `downward towards thebettom, again- Thus by provid.- ing suitable clearance a small amount of torsional vibration may exist without friction atvmountA, but as soon as the torsional deflectionv exceeds the value determined by the clearance at this point frictiondampingwill be introduced.

AS aresult O f these, improvements ,it will .b e. evident that an improved two-planeI engine mount has been provided. in which the engine is, in eifect,Y mounted in two laxially spaced,- bear?, ings one of which has no radial flexibility. and the other of which is designed to absorb radial vibrations ofthe engine. I t will also .beevident that a two-plane mountvhas Vbeen provided. inl which themount in one of these planes absorbs the torsional vibrations of the .engine .in shear, of the resilient elements.,tliiereohy VVwhile the other mount provides fr ictional damping of such torsional vibrations.I It willl further be evident that fore and aft deflectionsof tlfieHenyn gine due, for example, tolg,"loadvs.are absorbed in shear of the dampingband-at the. propeller end of the engine, while the rnountlB, clue to tory sional movements of the flexible attachments ebwtthe cross-genion@ peripeciaef Pharma which place the reSilQ. l me nts.-thereef a Shear; .resilently restrains Such for@ and .att movements. l

vvWhile 011e dfiralolay embodiment 0f theinvellr. tion has been described herein vand illustrated-in* the drawings, it istobennderstood that ,the inmation is.t .not limitait@ the. details. of; consiglio,-v tion or to the combination and arrangement of elements herein disclosed, but that .the invention covers all such variations` as come withinA the scope of the following claims.

-We claim:

- 1,. In an aircraft, a frame structure, an engine having a main power shaft, and means for supporting said engine on said frame structurecomprising two mounts at spaced locations along said shaft, one of said mounts including flexible and pivotal connections between saidA engine and fr ame structure for yieldingly resisting radial and torsional movements of the engine andA for providing relatively free or substantially unresisted fore and aft movements of the engine,` and the other mount comprising a bearing type. support for resisting said fore and aft movements of said engine.

2. In an aircraft, a frame structure, an engine having a crankshaft, andmeans for supporting said engine on said frame structure comprising two mounts at spaced locations along said crankshaft, one of said mounts including a mount ring encircling said engine and vdisposed in a plane perpendicular t0 the axis of said crankshaft, and means in the plane of saidr'ing for connecting said engine and ring including flexible connections to said ring yieldingly resisting radial; and torsional loads from said engine and a pivotal' connectionto said engine, and the other of 1said mounts .comprising confronting. annular grooved surfaces carried by said engine and frame structure, and aband of friction material fillingsaid grooves for resisting fore and aftmovements of said engine in shear of said material and dampj ing torsional movements'ofv said engine by the friction between said surfaces and said band.

3. In an aircraft,'a frame structure, an engine having a crankshaft, and means for supporting said engine on saidy frame structure at spaced locations along said crankshaft including ,a mount ring fixed tovsaid frame structure at' one of said locations having its center ,substantially coincident with the axis of said crankshaft, rigid struts connecting said engine and ring at spaced points about their peripheries for resiliently resisting torsional and radial loads from said engine while permitting fore and aft movements of said engine, said struts comprising A-frames disposed in the planes of said ring and each having its apex exibly connected to said ring and having its spaced extremities pivotally connected to said engine, and a mount at said other location having means for resisting fore and aft loads and radial loads from said engine while permitting movements due to torsional loads from said engine.

4. In an aircraft, a frame structure, an engine having a crankshaft, and means for supporting said engine at two spaced points along said crankshaft including a mount ring located in a plane transverse to the axis of said crankshaft and secured to said frame structure and having its center substantially coincident with said crankshaft axis, struts connecting said engine and ring at peripherally spaced points about said engine Yhaving their inner ends pivotally connected tasaid-engineandhaving their Outer'endsl. resiliently connected t9 said ring, said struts being vdisposed inthe plane of said ring, said( resilienty connections, comprising heads on the ends of said s tru ts whichsurround ythe crosssectional periphery of said ring, and resilient members Within said. heads bearingagainst diametrically Yopposite portions of the cross-sectionall periphery of said ringvand disposed-in the planes ofsaidv ring, and abearingtype support` Y for said engnespaced from said ring alongsaid axis including cooperating annular hangar and bracket members carriedby said frame structure,

5. Inan aircraft, anenginesuppcrting frame ,structure,A a radial enginehaving acrankshaft,

andmeans for supporting said engineat spaced points along said crankshaftincluding a mount ring disposed in a plane perpendicular to the axis of said crankshaft andl having its center substantially coincident with the axis of said crankshaft, a plurality of pads athperipherally spaced points about saidvengine, parspf struts pivotally connected at their inner end to adjacent pads and converging toward said ring, said struts eing disposed in the plane of said ring and each having at its outer ends a housing surrounding the cross-sectional periphery of said ring, and resilient segmental elements within said housing bearing against the latter and also 1against dianietrically opposite portions on the cross-sectional periphery of said ring, and a' support for said engine spaced from said ring including cooperating annular supporting surfaces carried by said structure and yengine respectively, and a band interlocking said annular surfaces against axial movement relative to each other and frictionally restraining relative movementsof said surfaces due to torsional loads from said engine. 6. In `an aircrafthaving an engine supporting frame structure; thecombination of an engine having a crankshaft comprising theaxisof rotation of the engine, ,andmeansforsuporting said engine at spaced points along said` axis inclu k ing a mount ringy carriedby the aircraft structure adjacent one end of the engine and having its center substantially coincident with said engine axis, rigid strutsonnecting,said engine ringV4 having like'ends connected tQJsaid engine ring respectively, said struts being substantially perpendicular to said crankshaft axis and each having a pivotal connection at one end to said engine and a flexible connection at its other end to said ring, the axes of said pivotal connections being disposed in the plane of said ring, and a bearing type support for said engine at its other end permitting rotational movement of said engine about its axis and including cooperating annular hangar and bracket surfaces on said aircraft structure and engine respectively, and a frictional band between said surfaces for controlling relative 'movement between said surfaces. 7. In an aircraft having an engine supporting frame structure, the combination of an engine having a crankshaft comprising the axis of rotation of the engine, and means for supporting said engine at spaced points along said axis including a mount ring carried by the aircraft structure adjacent one end `of the engine and having its center substantially coincident with said crankshaft axis, a plurality of struts connecting said engine and ring at peripherally spaced points about said engine, said struts being disposed in the plane of said ring and having their inner ends pivotally connected to said engine by pivots having their axes disposed in the plane of said ring for permitting free fore and aft movements of the engine and having flexible connections at their outer ends to said ring, each of said flexible connections including a head which surrounds the cross-sectional periphery of said ring and encloses rubber mounting elements disposed on diametrically opposite surfaces of the cross-sectional periphery of said ring and in the plane of said ring, whereby rotational movement of said engine about its axis places said mounting elements in shear and radial movements of said engine places said mounting elements in compression, and a bearing type support for said engine adjacent its other end including confronting annular surfaces on said airplane structure and engine, and a band of frictional material between said surfaces for controlling relative rotational movement therebetween.

8. In an aircraft having an engine supporting frame structure, the combination of an engine having a crankshaft comprising the axis of rotation of the engine, and means for supporting said engine at two spaced points along said axis including a mount ring through which said engine projects and the center of which is substantially coincident with said engine axis ,V a plurality of pads at peripherally spaced points on said en gine located in the plane of said ring, a plurality of pairs of diverging struts, each pair having its spaced ends pivotally connected to pads on said engine by pivots having their axes disposed in the plane of said ring and having at its other end mount heads enclosing portions of the cross-sectional periphery of said ring, resilient segments disposed in the planes of said ring and within said heads and bearing against diametercally opposite surfaces of the. cross-sectional periphery of said ring, means for preventing movement of said segments about said cross-sectional periphery as the result of fore and aft movements of the engine, and a bearing type support for said engine at a point spaced along its axis from said ring including confronting annular grooved surfaces on said airplane structure and engine, and a band of resilient material of less resilience than said segments occupying the grooves between said surfaces and interlocking the same against fore and aft movements of the engine.

9. In a mounting system for a radial aircraft engine having a crankshaft, a mount ring disposed in a plane substantially normal to said crankshaft, a plurality of iiexible mount brackets respectively connected to circumferentially spaced portions of said ring, and a plurality of strut members lying substantially in the plane of said ring pivotally connecting said engine and said brackets.

10. A system according to claim 9, in which said struts are pivotally connected to said engine about respective axes lying in the plane of said ring.

l1, A mount for an aircraft engine having a main power shaft, comprising, a circumferential row of resilient mount units disposed in a plane substantially normal to said shaft, means providing a torsionally and radially rigid and longitudinally non-rigid connection between said engine and said mount units whereby when the mount units are secured to a frame structure angular movements of said engine about the axis of said shaft and translational movements of said engine normal to the axis of said shaft are resiliently resisted by said mount units While longitudinal movements of said engine in the direction of said axis are substantially unresisted by said mount units, and a second supporting means spaced from said mount units and said connection for resisting longitudinal movements of said engine.

J OHN M. TYLER. ANDREW V. D. WILLGOOS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date Re. 22,403 Trott Dec. 7, 1943 1,834,907 'Irott Dec. 1, 1931 1,862,484 Lord et al June 7, 1932 2,121,429 Gluhareff June 21, 1938 2,342,577 Gehman Feb. 22, 1944 2,411,562 Thompson Nov. 25, 1946 FOREIGN PATENTS Number Country Date 493,328 Great Britain May 24, 1937 498,224 Great Britain Jan. 2, 1939 

